The Physics and Fantasy of Time Travel

Artist's impression of a wormhole. Credit: Pitris/iStock.

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About This Episode

Is time travel merely science fiction, or is it possible without contradicting the laws of physics? In this episode of StarTalk, Neil deGrasse Tyson and his guest, theoretical physicist Michio Kaku, examine time travel through the framework of quantum mechanics and the lens of science fiction movies and TV. Neil interviews both Christopher Lloyd, who played “Doc Brown” in the Back to the Future movies, and Michelle Gomez, who plays a female Time Lord, Missy, aka The Master, on Doctor Who. Join us as we relive the moment when Doc Brown fell off his toilet and invented the Flux Capacitor, and then listen as Neil, Michio and co-host Chuck Nice review some of the Eureka (or “That’s Funny?”) moments in scientific discovery, from William Herschel’s discovery of infrared light to Newton’s apple-inspired Theory of Gravity. Discover why common sense and Albert Einstein both fall short in their descriptions of time, and what Michio means when he talks about pretzels, forks and “whirlpools in the river of time.” Also up for discussion: H.G. Wells’ introduction of the concept of time as the Fourth Dimension in his 1895 classic, The Time Machine, and why physicists like Michio now think Stephen Hawking’s “Chronology Protection Hypothesis” is wrong, and why backwards time travel is possible thanks to quantum mechanics, the concept of the multiverse, and even general relativity. Find out what the 3 Classes of Impossibility are, and why teleporting and jet packs are Class 1, time travel and wormholes are Class 2, creating something out of nothing would be Class 3…. and Chuck’s wife letting him go to a strip club would be Class 4! All this plus timeless photons, parallel universes, the grand unification theory, Cosmic Queries, and this week’s “Nye in the City” segment when Bill Nye takes the DeLorean for a little time-traveling joy ride.

NOTE: All-Access Subscribers can listen to this podcast commercial-free here, as well as Neil’s extended interviews with Christopher Lloyd here, and Michelle Gomez here.